forked from lijiext/lammps
66 lines
2.0 KiB
Plaintext
66 lines
2.0 KiB
Plaintext
"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
|
|
|
|
:link(lws,http://lammps.sandia.gov)
|
|
:link(ld,Manual.html)
|
|
:link(lc,Section_commands.html#comm)
|
|
|
|
:line
|
|
|
|
mass command :h3
|
|
|
|
[Syntax:]
|
|
|
|
mass I value :pre
|
|
|
|
I = atom type (see asterisk form below)
|
|
value = mass :ul
|
|
|
|
[Examples:]
|
|
|
|
mass 1 1.0
|
|
mass * 62.5
|
|
mass 2* 62.5 :pre
|
|
|
|
[Description:]
|
|
|
|
Set the mass for all atoms of one or more atom types. Mass values can
|
|
also be set in the "read_data"_read_data.html data file. See the
|
|
"units"_units.html command for what mass units to use.
|
|
|
|
Most atom styles require masses to be specified. One exception is
|
|
"atom_style granular"_atom_style.html, where masses are defined for
|
|
individual atoms, not types. "Pair_style eam"_pair_eam.html defines
|
|
the masses of atom types in the EAM potential file.
|
|
|
|
I can be specified in one of two ways. An explicit numeric value can
|
|
be used, as in the 1st example above. Or a wild-card asterisk can be
|
|
used to set the mass for multiple atom types. This takes the form "*"
|
|
or "*n" or "n*" or "m*n". If N = the number of atom types, then an
|
|
asterisk with no numeric values means all types from 1 to N. A leading
|
|
asterisk means all types from 1 to n (inclusive). A trailing asterisk
|
|
means all types from n to N (inclusive). A middle asterisk means all
|
|
types from m to n (inclusive).
|
|
|
|
A line in a data file that specifies mass uses the same format as the
|
|
arguments of the mass command in an input script, except that no
|
|
wild-card asterisk can be used. For example, under the "Masses"
|
|
section of a data file, the line that corresponds to the 1st example
|
|
above would be listed as
|
|
|
|
1 1.0 :pre
|
|
|
|
[Restrictions:]
|
|
|
|
This command must come after the simulation box is defined by a
|
|
"read_data"_read_data.html, "read_restart"_read_restart.html, or
|
|
"create_box"_create_box.html command.
|
|
|
|
All masses must be defined before a simulation is run (if the atom
|
|
style requires masses be set). They must also all be defined before a
|
|
"velocity"_velocity.html or "fix shake"_fix_shake.html command is
|
|
used.
|
|
|
|
[Related commands:] none
|
|
|
|
[Default:] none
|